The invention relates to a device for driving a body which is suspended from two forked control gimbals by means of pivots for motion around two axes that are skewed with respect to one another, the body carrying out a tumbling and rotating motion based on the principle of the invertable link chain. Each control rod is connected to a shaft by means of the respective swivel bearing.
To assure that the body carries out the tumbling and rotating motion, at least one of the two parallel shafts is driven in a manner that the second shaft rotates due to the connection of the two shafts by means of the members of the link chain, comprising the control gimbals and the body.
However, the kinematics of the invertable link chain requires that the two shafts must rotate opposite to another and alternately with periodically alternating increasing and decreasing angular frequency if the object is to attain a regular motion of the simultaneously rotating and tumbling body hung on the control rods.
The body itself can serve as a container to accommodate the materials treated, which are subject to physical or chemical processes, achieving especially good effects with respect to the course of such processes due to the simultaneous tumbling and rotational motion. In particular, it can be used in the preparaton of mixtures whose components to be mixed are finely distributed, e.g., the mixing of very sensitive fine powders with lubricants for the extrusion of a paste or with color pigments, the powders being used in the production of plastic. Furthermore, the purpose of the body can be to homogenize, emulsify, or prepare powder mixtures such as for example a dry powdered metal.
Especially good effects are achieved with an oloidal body, which is a control body with two convex corners, that have the same constant curvatures and are in two orthogonal planes, whereby a casing surface has overall straight surface lines between these corners. In known oloidal bodies the motion is such that there is no change point with respect to the path already taken along the path of trajectory of the point of the oloid. The three dimensional path of trajectory of all points of the moved body is the explanation for the good mixing results when using such a body.
The same body, however, can also achieve the same good effects in processed materials, which surround the body, i.e., when used as a stirring member. Due to the special nature of its motion, as described above, the body is superior to any other merely rotating stirring member in which one must accept a separation due to centrifugal action and a shearing stress on the substance to be stirred due to the vortex formation and due to the high energy consumption corresponding to the generation of turbulent currents.
No shearing action occurs with the tumbling and rotating body described above when used as a stirring member in a liquid; the motion occurs without any break in the flow at the ends of the body and without the turbulence associated therewith. In the resulting motion of the liquid, air or oxygen that has been introduced is immediately dispersed and distributed homogeneously. Therefore, the device in a preferred embodiment is suitable for sanitizing water through the introduction of oxygen. This is only one of the numerous possibilities for its application.
The drive of the body via at least one shaft, or for a larger body and corresponding performance preferrably both parallel shafts, presents a number of technical problems due to the acceleration or delays required alternately at both shafts.
For the drive of just one shaft in a so-called pendulum drive, known from Ch-PS No. 496 912, a pivotable pendulum that is connected to the drive shaft is arranged to pivot on the same drive shaft. A control body which is automatically coupled with the shaft and is preferrably shaped like a crank which is pivoted at the pendulum, is on the pendulum. In operative connection with at least one reference point of the device, the crank causes a periodic, swiveling motion of the pendulum occurring as a function of the speed of rotation of the shaft. The crank is driven by means of a belt with half the speed of rotation of the same. The reference point of the device which is operationally connected to the crank is a guide slot in which the crankpin slides back and forth so that at every revolution of the drive shaft the pendulum makes two complete swings back and forth, whereby as the pendulum moves in the direction of rotation of the drive shaft by overlapping the two motions, the result is acceleration and as the pendulum moves in the opposite direction the result is delay. With this drive, which is rather expensive in its mechanical construction, only one of the two shafts can be driven so that for the size of the vessel to be displaced into tumbling and rotating motion, the limit is approximately a 500 liter content.
In order to drive both shafts having non-uniform angular speeds, various solutions have been proposed. However, they have been demonstrated to be unusable for industrial use. Thus, for example, the application of Cardan joints between the drive shafts and a motor-driven shaft, which forms a 45.degree. angle with the extended axis of the shaft, driven by it, because as is well-known with a Cardan joint, the angular speeds will change periodically, is known from DE-PS No. 1 145 455. However, this drive needs a lot of space; and due to the sharp 45.degree. distortion there is too much wear in the Cardan joints and shaft bearings. Thus the solution is not suitable for commercial usage.
A device, known from DE-PS No. 1 207 750, to solve this drive problem has a friction ball drive as a differential gear at one end of the shafts, whereas the second shaft is driven by way of a chain from a ring of this friction ball drive. However, due to the non-uniform angular speed of both shafts, there is so much friction in the differential gear that this solution is not suitable for continuous use in industry.
Furthermore, a drive having an elastic shaft couplings at the drive shafts, is known from DE-PS No. 3 034 331. Between the coupling disks on a circle, balls that are are arranged alternately in sequence, and pressure springs permit in this non-automatic drive a periodically repeating relative distortion of the coupling pieces to one another. Here the disadvantage is that the elastic yield in the drive system, which is effected by the forces due to inertia, do not conform with the required rhythm of motion. The cost of producing that which is accomplished by this solution is also relatively high.
It has also been mentioned that the body is used not only as a mixing container but also as a stirring member in a medium surrounding the body. The medium here can be, for example, water into which oxygen is to be introduced by means of the tumbling and rotating body, and in this case one needs only a body which is small in proportion to the volume of water contained in a container, as a stirring member.
As stated above, it is sufficient to drive only one of the two parallel shafts, whereby due to its connection via the links of the link chain to the driven shaft, the second shaft is rotated clockwise by the shaft. Friction, which the drive of the driven shaft must overcome, occurs in all links of the link chain and in the positioning of the non-driven shaft. When the shaft makes one revolution, the body, hung via the control rods on both shafts, also carries out the tumbling, rotating motion once until it reaches the same starting point. With respect to the tumbling and rotating motion it is now immatterial whether the one shaft is rotated in the machine frame, accommodating the two shaft positions, or whether the machine frame is rotated around the shaft as the central axis, whereby due to the connection between the two shafts, the shaft, which rotates and is arranged only to pivot at a distance from the center shaft in the machine frame, is rotated by means of the links of the link chain so that the hung body carries out the tumbling and rotating motion.